The telecommunication industry today is almost entirely focused on transporting ATM services over an MPLS core. However, there is interest from current ATM backbone service providers to make use of that backbone to provide enhanced services such as additional IP/MPLS services. In addition, the total footprint of ATM backbone networks today is much larger than MPLS based networks (node counts, etc.), since MPLS networks are relatively in a development stage. There are some markets and regions in the world where there exists ATM footprint and transport, but not yet full IP/MPLS or Ethernet. Therefore, it could be convenient to transport some IP/MPLS based services over existing ATM backbones instead of installing new equipment at all sites.
There is a need to extend the reach of IP/MPLS based services over an ATM backbone consisting of multi-service switches, without requiring the nodes to participate in the full PE function of the IP/MPLS based service, or without requiring an ATM link between the MPLS network and the ATM network.
Specifically, there is a need to provide a means for transporting an MPLS LSP or an LSP stack over an ATM backbone using a single SPVC or a SVC. Once an IP/MPLS service can be extended to locations currently using an ATM backbone, basic IP/MPLS based services could more conveniently be interconnected with minimal IP/MPLS service interoperability of a full PE node.